Conventionally, an information storage device is incorporated in, or connected to, electronics devices such as personal computers and word processors to store information. A hard disk drive is known as a type of information storage device. The hard disk drive is generally equipped with a disk serving as an information storage medium, a head which reads and writes recording bits from/to the disk, an arm which brings the head close to the disk and holds it, and an electromagnetic actuator which moves the head over the disk by driving the arm.
The recording densities of hard disk drives have been increasing with advances in personal computers and the like and have increased dramatically in recent years with increases in demand for personal computers and the like to handle images and music. With the increasing recording densities of hard disk drives, recording bits on the disks are becoming finer, the rotational speeds of the disks are becoming faster, and higher positioning accuracy and speed are required of the heads. Also, hard disk drives are achieving reductions in size, weight, and power consumption.
To deal with this situation, a hard disk drive has been proposed which is equipped with a piezoelectric actuator on the arm independent of the conventional electromagnetic actuator in order to position the head accurately at high speed.
However, piezoelectric actuators and hard disk drives proposed conventionally have such problems as insufficient head displacement, high drive voltage, large size and heavy weight, low impact resistance, and complex structure as well as high manufacturing cost required to achieve high accuracy.
These problems are not unique to hard disk drives and they are generally encountered by information storage devices designed to move the head by holding it with an arm.